Improvement in dies for cutting screw-threads



State of Connecticut, have invented certain Y and arrangement of theseveral parts, as will A. O is a handle screwed into the ring B,for

M. CARLYLE JoHNsoNfoF HARTFoRn, CONNECTICUT.

IMPROVEMENT IN m Es FOR; CUTTING SCREW-THREADS.

Specification forming part of Letters Patent Elm 904,048, dated February9, 1878. v

To all whom it may concern:

Be it known that 1, M. CARLYLE JOHNSON, of Hartford, in the county ofHartford and new and useful Improvements in Dies for OuttingScrew-Threads; and I do hereby declare that the following is a full,clear, and exact description thereof, whereby a person skilled in theartcan make and use the same, reference being had to the accompanyingdrawing, and to the letters of reference marked thereon.

Like letters in the figures indicate the same parts.

My improvement relates to such dies as are usually called open dies, orthose which release the bolt after the thread is cut, so as not torequire the motion of the die to be reversed and unscrew it from thethread.

' The object of my invention is to provide a better and simplerarrangement of parts for effecting the foregoing operation, to providefor the adj ustment of the diameter of the thread out to the exact sizerequired, and to permit of the cutters being readily removed and otherssubstituted for the purpose of cutting a different thread.

My invention consists in the construction be hereinafter described.

In the accompanying drawing, Figure l is a top view of my improved die.Fig. 2 is a side view of the same. Fig. 3 is a cross-section through themiddle, showing the working parts. Figs. 4, 5, and 6 are a top, end, andside view of one of the cutters. Figs. 7 and 8 are a front and side viewof one of the slides for operating the cutters.

A is the body of the die. B is a ring sur-. rounding the bodyAandresting upon a flange,

the purpose of turning it upon A. D is a col-. lar placed upon the bodyA, above the ringB, for the purpose of holding it in its position andforming the upper side of the groove in which it turns. This collar D issecured to the body A by means of screws E F, one or more of which alsoserves another purpose, which will be hereinafter described.

G G, &c.,- are slides moving up and down in suitable grooves in the bodyA. They are furnished with the projections H, which extend May 21 1878;application filed outward into the; grooves J in the ringB, so

ally in slots out in the collet L, the exterior of which fits into theinterior cavity of the body A. The tops of the slots are open; but thecutters are prevented from moving upward by means of the flange orfeather K, which fits into a corresponding groove in the collet.

The rear ends of the cutters K are inclined, and pass into the verticalsockets in which the slides G move, the slides being recessed to receivethem. The side of the rear part of the cutter is provided with a groove,M, into which fits the tongue N upon the slide G, both being inclined atsuch an angle that as the slide G moves up or down it moves the cutterout orin.

It will thus be seen that when the handle is turned hard to the left theslides are drawn down and the cutters projected toward the center in theposition for cutting a thread, and when the handle is turned to theright the cutters are withdrawn, so as to release the bolt upon whichthe thread has been cut.

The collet L is loose in the body A but the rear ends of the cutters,projecting into the sockets in the body, hold the collet firmly fromturning while the thread is being cut, and the inclined rear ends of thecutters, acting against the slides G as they are forced outward by thepressure of cutting the thread, press the collet firmly down into itsseat.

0 O are screws for adjusting the diameter of the thread cut. They passthrough hollow threads in the collet, and rest upon a shoulder of thebody A, as shown in the drawings, so as to elevate or depress the colletwhen in its lowest position, as it is when the threadis out. It will beobserved, that the effect of raising the collet is the same as that oflowering the slides G. By doing either the cutters are advanced towardthe center of the die, so that by this means the diameter of thread outcan be accurately adjusted. Two screws are shown in the drawing; butthere may be one or more, as is found most convenient.

Whenever it is desired to change the cutters so as to cutadifi'erentthread, the collet and out. ters are simply lifted out of the body ofthe die and others substituted. In lifting out the collet the cuttersslide inwardly, which releases them from the sockets in the slides G. Insubstituting another collet and cutters, or replacing the ones takenout, the slides G are raised and the rear ends of the cutters placed intheir proper sockets when the collet can be easily pressed down into itsplace.

The screw E (shown in Figs. 1 and 2) passes through the collar D, andpresses upon one of the segments of the body A between two of the slotsfor the cutters. This serves for an adjustment for the socket into whichthe collet L fits. If the collet fits too loosely, the screw istightened, which presses in the segment of the body A and tightensit.There may be one or more of such screws.

What I claim as my invention is- 1. The combination of the 'collet L andits ening the socket of the collet L, substantially as herein described.

M. CARLYLE JOHNSON.

' Witnesses:

THEO. G. ELLIs R. W. HAMILTON.

